The general aim of this project has been to improve electrical measurements of excitable membrane characteristics consistent with physical and chemical methods for the study of nerve membrane ionic channels. Two major approaches are used. The first involves the development of methods for rapid analysis of ionic channel conductances by means of computer controlled voltage clamp techniques. Programs for carrying out this analysis are developed. The second approach involves analysis of excitable membrane characteristics by means of frequency analysis of sinusoidally modulated action potential trains locked to a larger amplitude, higher frequency sinusoidal stimulus. Improvement of bridge impedance techniques to achieve greater accuracy are made. Admittance measurements on giant axons and an investigation of effects of polarizations for comparison with step and ramp techniques and ion conduction models are carried out. This project is supportive of a number of other projects in terms of the development of relevant hardward and software.